AJP - Regulatory, Integrative and Comparative Physiology, Vol 265, Issue 1 173-R179, Copyright © 1993 by American Physiological Society

ARTICLES

Volume-regulatory amino acid transport in erythrocytes of the little skate, Raja erinacea

J. K. Haynes and L. Goldstein
Section of Physiology, Brown University, Providence, Rhode Island 02912.

Skate erythrocytes swell in a hypotonic medium and then reduce their volume mainly by releasing the beta-amino acids taurine and beta-alanine. Although these amino acids exhibit a net efflux, Na(+)-independent influx is also increased. Both the reduction in cell volume and increase in amino acid transport are inhibited by several inhibitors of band 3-mediated anion transport, including 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) [L. Goldstein and S. R. Brill, Am. J. Physiol. 260 (Regulatory Integrative Comp. Physiol. 29): R1014-R1020, 1991]. The objective of the present investigation was to further characterize the mechanism of volume-activated amino acid transport. Na(+)-independent amino acid uptake was studied because of the ease in controlling amino acid concentrations. Na(+)-independent taurine uptake was observed to be linear over a range of 0.1-15 mM and was not inhibited by 10 mM beta-alanine, suggesting that the transporter may be a channel rather than a carrier. The uptake of a variety of amino acids was examined to characterize the size of the putative channel. Glycine, beta-alanine, taurine, proline, gamma-aminobutyric acid (GABA), and threonine exhibited volume-activated transport that was DIDS inhibited, whereas aspartic acid, leucine, methionine, and ornithine were not transported. On the basis of the size of these amino acids, it appears that molecules containing eight or fewer major atoms and having a molecular mass of < 125-131 Da are transported during volume activation but larger molecules are not. We estimate the size of the channel to be 5.7-6.3 A in diameter.

This article has been cited by other articles:

				M. W. Musch, A. B. Puffer, and L. Goldstein Volume expansion stimulates monoubiquitination and endocytosis of surface-expressed skate anion-exchanger isoform Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2008; 294(5): R1657 - R1665. [Abstract] [Full Text] [PDF]

				M. W. Musch and L. Goldstein Tyrosine kinase inhibition affects skate anion exchanger isoform I alterations after volume expansion Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2005; 288(4): R885 - R890. [Abstract] [Full Text] [PDF]

				D.-L. T. Koomoa, M. W. Musch, A. Vaz MacLean, and L. Goldstein Volume-activated trimethylamine oxide efflux in red blood cells of spiny dogfish (Squalus acanthias) Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2001; 281(3): R803 - R810. [Abstract] [Full Text] [PDF]

				K. Kirk Membrane Transport in the Malaria-Infected Erythrocyte Physiol Rev, April 1, 2001; 81(2): 495 - 537. [Abstract] [Full Text] [PDF]

				B. D. SCHULTZ, A. K. SINGH, D. C. DEVOR, and R. J. BRIDGES Pharmacology of CFTR Chloride Channel Activity Physiol Rev, January 1, 1999; 79(1): 109 - 144. [Abstract] [Full Text] [PDF]

				H. Guizouarn and R. Motais Swelling activation of transport pathways in erythrocytes: effects of Cl-, ionic strength, and volume changes Am J Physiol Cell Physiol, January 1, 1999; 276(1): C210 - C220. [Abstract] [Full Text] [PDF]

				B. Fievet, F. Perset, N. Gabillat, H. Guizouarn, F. Borgese, P. Ripoche, and R. Motais Transport of uncharged organic solutes in Xenopus oocytes expressing red cell anion exchangers (AE1s) PNAS, September 1, 1998; 95(18): 10996 - 11001. [Abstract] [Full Text] [PDF]

				M. W. Musch, E. M. Davis-Amaral, K. L. Leibowitz, and L. Goldstein Hypotonic-stimulated taurine efflux in skate erythrocytes: regulation by tyrosine phosphatase activity Am J Physiol Regulatory Integrative Comp Physiol, June 1, 1998; 274(6): R1677 - R1686. [Abstract] [Full Text] [PDF]